Surface Water Flood Flow Direction Maps for England

Risk of Flooding from Surface Water (RoFSW) flow direction maps model the direction of water flow during maximum flood speed. The Environment Agency produced the dataset using national-scale modelling enhanced with local authority data. It was last updated in April 2026.

Use Cases

• Model surface water flood propagation paths using the flow direction layer for a 1% annual chance scenario.
• Compare flood water movement patterns across different likelihoods (3.3%, 1%, 0.1%) to assess event severity.
• Integrate flow direction data with flood depth and hazard layers for comprehensive flood impact analysis.
• Validate local flood models by comparing their outputs against the national-scale flow direction data.

Strengths

• Data is derived from a national-scale model enhanced with compatible local modelling from lead local flood authorities.
• Provides separate geospatial layers for three distinct flood likelihoods: 3.3%, 1%, and 0.1% annual chance.

Limitations

• Specific technical details like spatial resolution, row/column counts, and file size are not provided.
• The primary file format is PDF, which is not ideal for direct computational analysis without conversion.

Provenance

Source

Environment Agency (UK).

Collection Method

Produced using national scale hydrological modelling, enhanced with locally produced modelling from lead local flood authorities (LLFAs).

Freshness

Last updated on 2026-04-07.

Geography

Covers England, as it is a UK Environment Agency product.